JPS5891053A - Manufacture of ceramic products - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a ceramic product, and more particularly to a method for manufacturing a ceramic product in which an organic binder is completely tic-degreased prior to firing.

When molding an unfired ceramic product by injection molding or extrusion molding, an organic binder is mixed with ceramic powder, heated and kneaded, and the ceramic powder containing this binder is molded into a predetermined shape. It will be done.

Ceramic products are produced by gradually heating the molded product to decompose and volatilize the organic binder contained in the molded product. It is obtained by going through a so-called degreasing process and then firing.

Therefore, during the above steps, whether or not degreasing is completely carried out has a great influence on the condition of the resulting product.

That is, conventionally, this degreasing method has been carried out in an inert gas atmosphere, such as nitrogen gas, at a temperature of 1 to 50 degrees at room temperature to about 800 degrees Celsius.
This was done by raising the temperature at a rate of C/hour.

However, in this conventional method, the surface of the molded body is degreased during degreasing, but the binder remains in the center, so after degreasing, the coefficient of thermal expansion between the ceramic and the binder, which is an organic substance, is Cracks and blisters were caused by the difference in

The present invention has been made to eliminate such conventional drawbacks, and includes a method for manufacturing a ceramic product, in which a ceramic powder and an organic binder are mixed, a molded product formed into a desired shape is degreased, and then fired. The purpose of degreasing is to provide a method for manufacturing ceramic products that does not cause cracks or blisters, in which the molded body is immersed in a solvent and heated.

In carrying out the method for manufacturing a ceramic product of the present invention, first, by a conventional method, ceramic powder such as silicon nitride, alumina, zirconia, etc. alone or with a sintering aid added thereto is mixed with polystyrene as an organic binder. , polyethylene, polypropylene, polybutadiene, paraffin, etc. are added in an amount of about 5 to 25%, and the resulting product is granulated as necessary, and then molded into a desired shape by injection molding, extrusion molding, compression molding, or other known molding methods. Manufacture.

Next, the molded body is immersed in acetone, ethyl alcohol, xylene, or other solvent (hereinafter referred to as a solvent), and while this state is maintained, it is heated to perform degreasing.

When degreasing is performed by heating a molded object in a solvent as described above, the binder is extracted and comes out to the surface layer, so it is more complete degreased than when heated without using a solvent. be able to.

After degreasing in this manner, the molded body is fired by a conventional method to produce a ceramic product.

As the above-mentioned firing method, any method such as furnace sintering, real press, hot isopressure pressing, etc. can be used.

Next, examples of the present invention will be described.

Example Using silicon nitride as the ceramic powder, 20% polystyrene was added as an organic binder, and dioctyl phthalate and stearin e k were added and mixed.The ceramic material powder was granulated into granules with a particle size of about 2 mm by a conventional method. This is then injection molded so that the − side is ’50.
A cube-shaped molded body of mm 2 was produced.

Next, this molded body is immersed in acetone and heated from room temperature to
Degreasing was performed by heating to 0°C.

When ten samples of the molded articles degreased as described above were examined for the occurrence of cracks and blisters, no defects were observed.

Furnace sintering was also performed on these compacts by heating them at 1750° C. in nitrogen gas, but no defects were observed as in the case after degreasing.

On the other hand, when a molded body having the same composition and the same dimensions as in the example was degreased in a nitrogen gas atmosphere,
Defects were found in 8 out of 10 pieces.

(7317) Representative patent attorney close aide Kensuke (and 1 other person)

Claims (1)

[Claims] 1. A method for manufacturing a ceramic product in which a ceramic powder and an organic binder are mixed, a molded product formed into a desired shape is degreased and fired, and the degreasing is performed by immersing the molded product in a solvent and heating it. A method for manufacturing ceramic products characterized by: